Sources told the news network that the investigation, which is conducted by the White Collar Crime division of the FBI, is a "very high priority."

One source further stated that the bureau collected "a lot of" evidence, adding that "there is an avalanche of new information coming every day."

Baier also said that the Clinton Foundation probe is more expansive than previously thought, and that many individuals have been interviewed several times throughout the course of the investigation.

Sources said that they are "actively and aggressively pursuing this case" and that investigations are likely to continue.

Baier added that when he pressed the sources about the details of both probes, they told him that they are likely to lead to an indictment.

Additionally, Baier reported that according to Fox News's sources, Clinton's private email server had been breached by at least five foreign intelligence hackers. FBI Director James Comey said in July that he could not say definitively whether her server had been breached.

Correction: An earlier version of this story said Fox News' sources were from within the FBI. Baier said the two sources have "intimate knowledge of the FBI investigations." Updated Nov. 3 at 2:12 p.m.